<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>lesson 41</title>
  <script src="https://unpkg.com/vue@next"></script>
</head>
<body>
  <div id="root"></div>
</body>
<script>


  // CompositionAPI 的语法下，获取真实的 DOM 元素节点
  const app = Vue.createApp({
    setup() {
      const { ref, onMounted } = Vue;
      const hello = ref(null);
      onMounted(() => {
        console.log(hello.value);
      })
      return { hello }
    },
    template: `
      <div>
        <div ref="hello">hello world</div>
      </div>
    `,
  });
  
  const vm = app.mount('#root');
</script>
</html>
